Basically, there are two methods of growing mushrooms commercially: the bed and the tray methods. While the apparatus of this invention may be employed in the latter procedure, this invention will be described with particular reference to its application in the shelf (bed) system method.
In the tray system mushrooms are grown in wooden trays which range in size from 4 ft..times.4 ft. to 4 ft..times.8 ft. and so on. The major advantage of the tray system over the shelf system has been the ability to mechanize all of the mushroom growing operations. This lowers the use of manual labor in moving material. Some of the main drawbacks with tray systems are damage to the trays and costs. In moving the heavy trays from one machine to the next and from room to room quite a bit of wear and tear on the trays is experienced due to the weight of the compost in the tray. Another disadvantage has been the high cost of the tray handling machinery and the need for qualified electricians and fitters to maintain the machinery. Damages to wooden trays, the need for high cost machinery, and the need for full-time electricians and fitters all add up to high operation costs in the tray system.
Until recently, in the shelf system, all of the operations (filling, spawning, casing, picking, emptying of the shelves) were done by hand. The reason for this has mainly been due to the size and shape of the building and its necessary contents. In a growing operation utilizing the shelf system mushrooms are grown in shelves which are about 65" wide and about 60 ft. long. These are usually stacked in a superimposed position, six or so in a tier, in adjacent tiers that are about 12 ft. high. The vertical distance between these superimposed shelves is about 24". The dimensions of mushroom buildings, however, often varies from plant to plant. Two or four of the above mentioned tiers are usually placed in a growing room. The aisles between adjacent tiers are generally no more than 32" wide. The head room from the top of the top shelf to the ceiling is also usually limited to about 3 feet. At the front and rear of each tier only about 3 ft. of space is left between the shelf and the respective wall of the building. To further complicate the problems from a material handling standpoint, the only access into these growing rooms usually is a door which is about 32" wide and only 6 ft. high. The above description will make it obvious that room for machinery and attendant personnel is very limited and that all the mushroom growing operations have previously been limited to time consuming, arduous manual labor. Further, the compact arrangements just described are quite typical, since much of the success of a commercial operation depends upon proper use of heat, air and other environmental factors. Since there are a large number of commercial shelf systems in use, the need for mechanization has been and is great.
In the cultivation of mushrooms a growing medium is placed in the above mentioned shelves to a depth of about 12". After all of the shelves in a growing room are filled with the medium (compost), the entire room is sealed off, and the compost is allowed to heat up thereby completing pasteurization. After pasteurization the compost is spawned (planted with the seed). Approximately 14 days after spawning, the compost is covered with a layer of soil (casing) to induce fruiting of the mushroom. In the past this soil was carried in buckets and dumped on the bed manually. After the buckets were dumped on the compost, it was necessary to level the layer of soil to form an even layer. Not only is this work difficult, but it is hardly possible to apply a uniform layer, a most important factor in the production of mushrooms. The application of this layer of soil triggers a micro-biological activity between the medium (compost) and the casing without which few, or no mushrooms at all, are produced.
Accordingly, a purpose of this invention is the provision of apparatus for effecting the casing operation efficiently with a minimum of personnel. Another aim is providing apparatus which can be easily installed and moved around in the confined spaces of the quarters normally found in the industry using the shelf system. A still further goal is assuring the production of a uniform layer of casing. Another purpose is to eliminate or minimize contamination by providing for automatic movement of materials by machinery with but little or a minor amount of direct contact of material by workers. These and further objectives will appear hereinafter.